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Road pavement costs expend a significant share of financial resources in road construction, and finding the optimal pavement thickness design with minimal cost remains a concern that can be determined using intelligent search algorithms. This study aims to evaluate the performance of the particle swarm optimization (PSO) algorithm based on Iranian Highway Asphalt Paving (IHAP) Code 234. Thus, using the PSO algorithm, the problem of pavement thickness design was solved numerically, and a simulation–optimization technique was devised. Comparing PSO and the linear algorithms (LP) indicates that PSO is accounted as an optimal pavement thickness design regardless of different ranges of the equivalent single-axle loads (ESALs) and resilient moduli (Mr). Considering the four-layer and three-layer pavement designs revealed that the different bitumen-stabilized bases in the four-layer design are not cost-effective. Moreover, the PSO design resulted in 22–29 percent cost savings at various ESALs and Mr; however, the three-layer design was 23–31 percent less expensive.

This paper deals with construction site layout planning (CLSP) problem in the context of a multi-objective optimization model. According to the operational plans in Iran, in execution of the construction projects, special places are considered to accommodate the respective facilities in the jobsite. As an important part of project execution, the site layout planning has always been of concern for clients, contractors and consultants which is majorly intended to layout the facilities by properly arranging the them such as offices, warehouses, residences etc. such that materials, information and staff could be transferred optimally. Noteworthy, an appropriate layout improves level of safety and efficiency, reduces transport costs, prevents formation of bottlenecks and obstructions ahead of materials and equipment transfer particularly in mega projects. The site layout could be arranged with respect to the decision maker’s opinions based on different criteria. The model’s target functions include maximizing the safety level of construction facilities along with minimizing the corresponding costs and finally, minimizing the respective risks in potential areas. The constraints involve unique layout of each facility as well as the allowable distance between various facilities. Given the fact that the CSLP is classified as an NP-hard problem, it would be difficult to derive viable results using mathematical models whose solution process is time-taking as well. In this respect, to solve the numerical examples in a realistic representation scheme, NSGAII and MOGWO metaheuristic algorithms are applied. In order to compare efficiency of the proposed algorithms with the results derived from mathematical model solution, a number of standard measures have been used. The results indicate that the Pareto frontier produced by the proposed algorithms in numerical examples, is significantly in agreement with the optimal Pareto frontier in the case of small sizes approving great efficiency of the algorithms. Moreover, it was observed that in medium and large sizes, performance of the MOGWO surpasses that of NSGAII, making it appropriate for real-size cases. Lastly, results of this study could be considered as a management tool to make optimal strategic decisions aiming to develop the CSLP studies.

Since road pavements consume a significant portion of the financial resources of construction costs, design engineers aim to find an appropriate pavement thickness design with minimum possible cost. The optimal design can be located using intelligent search algorithms. This study compares the performance of genetic algorithm and particle swarm optimization to determine the efficacy of intelligent algorithms in determining the economically optimal pavement thickness design. The software required to implement the two algorithms for solving the pavement design and the simulation–optimization model were developed. Then, nine completed projects in Khuzestan, in Southwestern Iran, were evaluated using the manual design approach of consulting engineers, and the projects’ capabilities were compared by applying the programs developed for the two algorithms to the projects. The results indicated using GA and PSO reduced design costs by 9–26.5% and 5–25%, respectively compared to the manual design, and GA outperforms PSO by 1–5.5% regarding cost savings.

This study presents a new hybrid framework based on the multi-criteria decision making in order to rank the potential site layout locations by consideration of the cost and safety criteria in the Mehr Construction Project in Tehran, Iran. To this end, all of the criteria in selecting suitable potential locations are extracted from the research literature and the most effective ones, which are matched with existing conditions in Tehran are considered based on the opinion of experts,. Then, the proper locations for site layout are determined as the potential alternatives and ranked by experts based on the structure. According to the data collected from the questionnaires, the weights of the selected criteria are calculated using Best Worst Method (BWM) and the final ranking of the locations is performed using two Gray Relational Analysis and VIKOR methods. The computational results indicate that both VIKOR and GRA methods yield the same ranking. However, a method with higher reliability should be used to select the best potential location of construction site layout. Therefore, the sensitivity analysis of final outputs on the parameters existing in VIKOR and GRA methods is used in order to rank the alternatives and select the best approach. According to the computational results, the GRA method provides higher robustness compared with the VIKOR method. Accordingly, the ranking obtained from the GRA method is employed as the final solution in implementing the case study.

The vital need for river management and prediction of bank erosion processes is obvious. Riverbank erosion is one of the major sources of sediment for many rivers across the world. In this research, a combination of morphology methods, satellite imagery and BSTEM model were used for stability analysis of Bashar River. Comparison of the results of the BSTEM model indicated that the averages of maximum lateral retreat in cross sections of 1 to 5 were 128, 210, 200, 37 and 65 cm; the average of total eroded area were 2.01, 4.1, 5 36, 0.7 and 2.65 m2; the failure width were 1.73, 3.12, 2.32, 8.56 and 2.65 m, and the factor of safety were 0.34, 0.33, 0.27, 1.07 and 0.79, respectively, indicating the instability of the studied cross sections. On average, the maximum lateral retreat and the minimum factor of safety occurred in the floods peaking at the 537 and 912 m3/s, respectively. The results of the application of the BSTEM model in the selected reach indicated the instability of this reach of the river.

Suspended sediment generation is a predominant process in most watersheds, which has an important role in total sediment yield reached the main outlet of the watershed. However, the determination of contribution of main sediment sources in the watersheds, as one of fundamental bases of sediment management practices, has been rarely considered. Hence, on the present case study was conducted Galazchai Watershed in West-Azarbaijan Province, Iran, with an area of some 103 km2 to investigate the contribution of wash and bed sediment sources in total suspended sediment yield. Towards this attempt, sediment samples from 12 storm events which occurred during the spring of 2014 and autumn of 2014, were collected and subjected to laser particle size distribution measurement. The suspended sediment particle size distribution results verified a significant contribution of wash load with an average of 89.45± 11.95% in suspended sediment supply for the study storms. The mean contribution in the spring of 2014, summer of 2014 and autumn of 2014 were founded to be 92.17, 90.71 and 85.80%, respectively. The results consequently verified the necessity of special attention to management of watershed upstream in order to plan a proper sediment management of the study watershed.

Introduction: The critical role of the rivers in supplying water for various needs of life has led to engineering identification of the hydraulic regime and flow condition of the rivers. Hydraulic structures such dams have inevitable effects on their downstream that should be well investigated. The reservoir dams are the most important hydraulic structures which are the cause of great changes in river flow conditions. Materials and Methods: In this research, an accurate assessment was performed to study the flow regime of Karkheh river at downstream of Karkheh Reservoir Dam as the largest dam in Middle East. Karkheh River is the third waterful river of Iran after Karun and Dez and the third longest river after the Karun and Sefidrud. The Karkheh Dam is a large reservoir dam built in Iran on the Karkheh River in 2000. The Karkheh Reservoir Dam is on the Karkheh River in the Northwestern Khouzestan Province, the closest city being Andimeshk to the east. The part of Karkheh River, which was studied in this research is located at downstream of Karkheh Reservoir Dam. This interval is approximately 94 km, which is located between PayePol and Abdolkhan hydrometric stations. In this research, 138 cross sections were used along Karkheh River. Distance of cross sections from each other was 680m in average. The efficient model of HEC-RAS has been utilized to simulate the Karkheh flow conditions before and after the reservoir dam construction using of hydrometric stations data included annually and monthly mean discharges, instantaneous maximum discharges, water surface profiles and etc. Three defined discharges had been chosen to simulate the Karkheh River flow; maximum defined discharge, mean defined discharge and minimum defined discharge. For each of these discharges values, HEC-RAS model was implemented as a steady flow of the Karkheh River at river reach of study. Water surface profiles of flow, hydraulic parameters and other results of flow regime in HEC-RAS model were obtained for the conditions before and after the construction of the Karkheh Reservoir Dam and then it was reviewed and analyzed. Results and Discussion: By exploiting the Karkheh Reservoir Dam, the river flow was changed from the natural condition to the regulatory situation. The results indicate that the river flow was considerably declined because the regulatory effect of the reservoir dam which has contributed to the great alternations at hydraulic parameters of the river. For example, the mean annual discharge of the Karkheh River shows 44pecent reduction during the time period of simulating (after the dam construction in comparison with the natural river flow before construction of reservoir dam) in PayePol hydrometric station. Flow velocity of Karkheh River is influenced by discharge, slope of the river channel and geometry of cross section. By increasing the river flow, the flow velocity has increased and there is a significant difference between pre and post-dam condition at the mean velocity of river flow in different sections. The flow area is directly influenced by river discharge and there is a significant difference in the maximum defined discharge before and after dam construction. The width of water surface is a parameter of the geometric situation of the river cross section that also shows the maximum width of the cross sections, passing discharge through the desired cross section. Since Karkheh River has a relatively large water surface width, it has a high wetted perimeter. For this reason, the Karkheh river hydraulic radius is usually low. The significant reduction of all these quantities is for reduction of flow rate by construction of Karkheh Reservoir Dam. Studying the water surface profiles represents reduction of water level in the longitudinal profile of Karkheh River and water level of hydrometric stations by construction of the Karkheh Reservoir Dam. Also, due to the reduction of the discharge in the downstream of Karkheh Dam, all hydraulic parameters of the river such as flow velocity, flow area, width of surface water, hydraulic depth, shear stress and the hydraulic radius have been changed. In general, it can be concluded that the construction of a large dam such as Karkheh Reservoir Dam has a significant effects on the flow regime conditions at river downstream. Our survey would be helpful for environmental, geological and ecological experiments on effects of dam construction and for engineering next hydraulic structures on such rivers.

Project management components are key elements. Factors associated with failure and nonfulfillment are faced the project with main challenges. In this research to understand the relationship between PMBOK areas in the oil and gas industry construction project management better, some evaluation parameters were determined. Based on 10 knowledge areas & experience of project case studies were determined as a comprehensive hypothesis and it is called: "Influence of PMBOK area on oil & gas construction project management industry." This study contains a lot of professionals & experts points of view in this context with 266 people, 248 questionnaires were analyzed correctly. Following the results of testing of testing P-values, significant level is less than 0.05 and positive regression coefficient with high reliability of 99% in all stages of hypothesis can be said that there is a significant relationship between the studied cases and project management knowledge areas. Since the fact that integration management has the largest scope, influence of all items in this section were measured as an impressive component. The results of this study were suggested as an instruction in order to improve the projects in the oil & gas industry. It can be added to the success of projects by reducing the exciting challenges such as: delays, increase the cost and negative risks of changes, with maintain the quality and customer satisfaction. [ABSTRACT FROM AUTHOR]